Molecular and ultrastructure characterization of two nematodes<i>(Thelandros scleratus and Physalopteroides dactyluris)</i>based on ribosomal and mitochondrial DNA sequences

Goswami, Urvashi; Chaudhary, Alka; Verma, Chandni; Singh, Hridaya Shanker

doi:10.1515/helmin-2016-0013

Cited by 10 publications

(4 citation statements)

References 28 publications

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“…Regarding molecular relationships, only four of the > 90 Parapharyngodon and Thelandros have been sequenced, representing < 5% of the described species. Genetic information, however, is inconclusive regarding the validity of the genera, since the two Thelandros species available ( T. tinerfensis and T. scleratus , the latter formerly assigned to Parapharyngodon scleratus ) are part of a clade including Parapharyngodon sequences (Chaudhary et al ., 2015, 2017; Goswami et al ., 2016). Therefore, there is a need for inclusion of other representatives to assess the evolutionary relationships and taxonomic validity of these two genera.…”

Section: Introductionmentioning

confidence: 99%

The importance of integrative approaches in nematode taxonomy: the validity of Parapharyngodon and Thelandros as distinct genera

Sousa¹,

Jorge

Carretero³

et al. 2018

J. Helminthol.

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Despite the advances of molecular tools, new nematode species are still described mainly based on morphological characters. Parapharyngodon and Thelandros are two genera of oxyurids with unclear related taxonomic histories. Here we use morphological characters (linear measurements and categorical variables) and genetic information (18S rRNA, 28S rRNA and COI partial gene sequences) to confirm the relationships between representatives of these two genera and to determine whether they can be discriminated morphologically. Genetic results confirm the existence of two main clades, mostly congruent with Parapharyngodon and Thelandros genera but with several discordances. Thelandros is polyphyletic, with two of the species analysed (T. filiformis and T. tinerfensis) being part of the Thelandros clade, but with a third one (T. galloti) falling within the Parapharyngodon clade. Regarding the Parapharyngodon clade, P. cubensis, P. scleratus and Parapharyngodon sp. from Mexico form congruent lineages, while most P. echinatus samples cluster in another group, with one exception. Interestingly, P. micipsae samples are scattered across the Parapharyngodon clade, suggesting that they were misidentified or rather represent alternative morphotypes of other species. Morphological analysis identified the length of the tail, number of caudal papillae, position of the nerve ring, presence of caudal alae and length of the lateral alae as reliable characters to distinguish between Parapharyngodon and Thelandros genetic clades. Our study highlights the current taxonomic inconsistency in these groups, mainly derived from the exclusive use of morphological data. As such, we advocate for the routine implementation of molecular data in nematode taxonomic studies.

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Section: Introductionmentioning

confidence: 99%

The importance of integrative approaches in nematode taxonomy: the validity of Parapharyngodon and Thelandros as distinct genera

Sousa¹,

Jorge

Carretero³

et al. 2018

J. Helminthol.

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“…Therefore, morphological identifi cation needs the use of molecular analyses to supplement the proper identifi ca-tion and validation of species. Molecular tools are frequently used in nematode identifi cation and systematics (Gasser, 2001;Nadler et al, 2005;Mattiucci & Nascetti, 2008;Borges et al, 2012;Jones et al, 2012;Liu et al, 2013;Pekmezci et al, 2014;Di Azevedo et al, 2015;Goswami et al, 2015Goswami et al, , 2016. In this study, supporting morphological and molecular information is provided for P. spiculogubernaculus Agarwal, 1958 from the freshwater fi sh H. fossilis collected from Ghazipur, Delhi, India.…”

Section: Introductionmentioning

confidence: 59%

Procamallanus spiculogubernaculus Agarwal, 1958 (Nematoda: Camallanidae) from Stinging catfish, Heteropneustes fossilis in India: morphological characterization and molecular data

et al. 2017

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SummaryThe nematode, Procamallanus spiculogubernaculus Agarwal, 1958 was found from the Stinging catfi sh, Heteropneustes fossilis (Bloch, 1794) from Ghazipur, Delhi, India. Morphological characterization, including scanning electron microscope observation supplemented with DNA sequences is provided. Specimens recently found are characterized by the presence of an unlined buccal capsule having a small basal ring, esophagus muscular and glandular, vulva position is slightly post-equatorial, tail conical, long, and ending in three digit-like processes, phasmids present at about mid-length and cloaca located at the posterior end. In this study the species P. spiculogubernaculus is validated on the basis of molecular data after 47 years from its original description. In the scanning electron microscope examination, the topology of mouth and sensory pits in anterior portion, while the phasmids and digit like processes in posterior portion is clearly observed. Molecular data of the 18S ribosomal RNA and mitochondrial cytochrome c oxidase subunit 1 (cox1) gene were analyzed. Molecular phylogenetic analyses supported the validity of Procamallanus spiculogubernaculus and confi rmed the paraphyletic status of the members of Procamallanus, Spirocamallanus, Camallanus and Paracamallanus. Taxonomic status of members of the family Camallanidae are briefl y discussed along with the results of the systematic evaluation of P. spiculogubernaculus based on molecular data.

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“…Some authors, for example Moravec et al (1997), considered that the morphological features of Thubunaea and Physalopteroides have rarely been analysed using techniques such as SEM, and that these observations could provide detailed information to assess the validity of these two genera. However, to the best of our knowledge, SEM studies are still scarce in both genera, being available for only three species of Thubunaea (Moravec et al 1997, Pazoki and Rahimian 2014, Ramallo et al 2016) and two species for Physalopteroides (Elwasila 1990, Goswami et al 2016). The specimens described in the present study show a symmetrical cephalic structure, as in Thubunaea .…”

Section: Resultsmentioning

confidence: 99%

New records of helminths of Sceloporus pyrocephalus Cope (Squamata, Phrynosomatidae) from Guerrero and Michoacán, Mexico, with the description of a new species of Thubunaea Seurat, 1914 (Nematoda, Physalopteridae)

de¹,

López-Caballero²,

Mata-López³

2017

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A total of 61 specimens of the Red-headed Spiny Lizard Sceloporus pyrocephalus Cope (Phrynosomatidae) collected during the breeding season (June/July 2003, 2004 and 2005) from Western Mexico were examined for helminths. The morphological characterization of the helminths found was made through light microscopy and scanning electron microscopy. Nine taxa of helminths were identified, two cestodes: Mesocestoides sp. and Oochoristica sp., and seven nematodes: Parapharyngodon ayotzinapaensis Garduño-Montes de Oca, Mata-López & León-Règagnon, 2016, Parapharyngodon tikuinii Garduño-Montes de Oca, Mata-López & León-Règagnon, 2016, Parapharyngodon sp., Physalopterinae gen. sp., Skrjabinoptera scelopori Caballero-Rodríguez, 1971, Strongyluris similis Caballero, 1938 and a new species of Thubunaea Seurat, 1914. Larvae of Mesocestoides sp. and Physalopterinae gen. sp. were found in the body cavity and digestive tract, respectively. Excluding the species of Parapharyngodon Chatterji, 1933, S. pyrocephalus is recorded for the first time as a host of the remaining seven taxa of helminths. Additionally, Thubunaea leonregagnonae sp. n. is described and illustrated as a new nematode species, parasite of S. pyrocephalus from Mexico. This new species can be differentiated from the majority of its congeners by the absence of spicules, the particular pattern of caudal papillae in males and the small ratio of oesophagus length:male total body length (0.1–0.16).

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Molecular and ultrastructure characterization of two nematodes(Thelandros scleratus and Physalopteroides dactyluris)based on ribosomal and mitochondrial DNA sequences

Cited by 10 publications

References 28 publications

The importance of integrative approaches in nematode taxonomy: the validity of Parapharyngodon and Thelandros as distinct genera

The importance of integrative approaches in nematode taxonomy: the validity of Parapharyngodon and Thelandros as distinct genera

Procamallanus spiculogubernaculus Agarwal, 1958 (Nematoda: Camallanidae) from Stinging catfish, Heteropneustes fossilis in India: morphological characterization and molecular data

New records of helminths of Sceloporus pyrocephalus Cope (Squamata, Phrynosomatidae) from Guerrero and Michoacán, Mexico, with the description of a new species of Thubunaea Seurat, 1914 (Nematoda, Physalopteridae)

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